Abstract :
Oxidized (001) surfaces of both GaAs crystals and Ga0.7Al0.3As alloys are found to exhibit characteristic reflectance anisotropy (RA) spectra in the range 1.5–5.5 eV. A microstructure model of GaAs/oxide interface is proposed to treat the observed spectra within a quasi-microscopic theory of reflectance anisotropy developed for multilayer dielectric arrangements. Quantitative agreement between measured and calculated RA spectra shows the principal spectral features to be related to local-field effects at the GaAs/oxide interface, which is typical of A3B5 compounds.
